Hydroelectric by Achsah Shaji

Water converted to usable energy:

Water is converted into usable engery by water allowing to flow through tunnels in the dam to turn turbines and thus drive generators. The sun evaporates water from the sea and lakes, which forms clouds and falls as rain in the mountains, keeping the dam supplied with water, for free.

Water used today:

This type of energy is used today through dams. Twho examples of dams are the Hoover Dam and the Niagra Falls. The Hoover Dam has great height of water, it arrives at the turbines at high pressure, wich means taht we can extract a great deal of energy from it. The water then flows away down the river as normal.

Advantages:

Once the dam is built, the energy is virtually free.
No waste or pollution is produced.
Much more reliable than wind, solar or wave power.
Water can be stored above the dam ready to cope with peaks in demand.
Hyro-electric power stations can increase to full power very quickly, unlike other power stations.

Disadvantages:

The dams are very expensive to built.
Building a large dam will flood a very large area upstream, causing problems for animals that used to live there.
Finding a suitible site can be difficult.
Water quality and quantity downstream can be affected (impact on plants).